A/C Compressor Inoperative Due To Low Ambient Temperature - keywords air cold condition HVAC intermittent

This PI was superseded to update models and model years. Please discard PIT4211A.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

When diagnosing an HVAC system concern, some technicians may find that the A/C compressor will not engage because the ambient temperature is too low as determined by the Ambient Temperature Sensor. The A/C compressor is disabled in temperatures below 2 degrees Celsius (36 degrees Fahrenheit). Typically this will occur when the vehicle is parked outside in temperatures below 2 degrees Celsius (36 degrees Fahrenheit) and then brought into the shop. Since the ambient temperature does not update instantly, it will be necessary to perform an instant update of the ambient temperature sensor in order to proceed with diagnostics.

To perform an Instant Update of the Ambient Temperature Sensor, press and hold the Recirc button and A/C button on the HVAC Control Head simultaneously. Within a few seconds, the DIC should display the current temperature.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.